This project is intended to determine the organization and regulation of the expression of Adenovirus genes during the lytic cycle and in transformed cells. The regulation of early gene expression is being studied by defining the lesion in Ad5 host range mutants, utilizing hybridization selection and cell-free translation of mRNA and appropriate DNA sequencing. The control of the coordinate expression and possible modulation of the mRNAs contained within the major late transcription unit in being studied in infections of synchronized cells. Various adenovirus transformed cell lines will be analyzed to determine the structure of viral mRNAs expressed and to define the polypeptides they encode. Also full length cDNAs of the mRNAs expressed from the transforming region will be prepared and characterized. These will be incorporated into the appropriate SV40 vector and used in combinations to transfect primary rodent cells in order to attempt to dissect the events that establish the transformed cell phenotype.